Perceived Crash Causes

As in 1994, each group
was asked to make a list of factors they perceive to be major causes of
crashes on the Capital Beltway. Then, each participant was asked to select
up to three items from the list that he/she considers to be among the
most important causes.

In the 1997 groups,
unsafe driving behaviors continued to be the major concern of most participants.
Driving conditions, including bad weather and traffic congestion, was
the second most serious category of concerns in the 1997 focus groups,
followed by roadway design and maintenance factors, trucks and law enforcement
(or lack thereof).

There was a perceptible
difference between the proportion of 1997 and 1994 participants who designated
one or more unsafe driving behaviors among the top three causes of Beltway
crashes. In total, the 1997 participants designated about two items each
from this category, compared to about one item each among 1994 participants.
Excessive speed, aggressive driving, inattention, unsafe lane changing
and tailgating were the most frequently designated behaviors in the 1997
groups. The major difference between the 1997 and 1994 groups is that
aggressive driving was designated by 38 percent of the 1997 participants,
up from only 2 percent in 1994. Also, far more 1997 participants (48 percent)
identified excessive speed as a major crash cause than 1994 participants
(23 percent).

Interestingly, the
aggressive driver groups designated speed as a major crash cause more
frequently (65 percent) than the 1997 general driver groups (38 percent).
As might have been expected, fewer participants in the aggressive driver
groups (15 percent) identified aggressive driving as a major crash cause
than participants in the general groups (53 percent). Another marked disparity
between the two types of groups was that 35 percent of the aggressive
driver group members designated unsafe lane changes as one of their top
three items compared to none in the general groups.

There was not much
overall difference between 1994 and 1997 with regard to the proportion
of participants who blamed driving conditions for crashes on the Beltway.
There was, however, a difference in which conditions received focus. In
1994, 44 percent of the participants named congestion as a major cause
of Beltway crashes. In 1997, only 23 percent did. Conversely, 37 percent
of the 1997 group members said that bad weather was a major crash cause
compared to only 9 percent in the 1994 groups.

In aggregate, roadway
design and maintenance factors comprised the top category of crash causes
among 1994 participants (designated "major" by 97 percent).
In 1997, however, the category declined to third rank, with only 33 percent
naming design and maintenance items as major crash causes. While shared
acceleration/deceleration lanes (called "merge lanes" by most
participants) remained the top item and did not change much. Construction,
lane markings signs and lane drops declined sharply as major concerns.

There was also noticeably
less emphasis on trucks in 1997 than in 1994. In 1994, 20 percent blamed
trucks as a major crash cause. In 1997, the proportion declined to 4 percent.

The following table
shows the percentage of participants who designated each item as one of
the three most important causes. If an item was listed as a crash cause
but no participants included it in their three most important items, it
is represented as 0 percent. If an item was not mentioned by a group,
it is represented as "--" in the table. It should be noted that
when items are aggregated, they can and sometimes do, total to more than
100 percent because each participant could select up to three items.

Table 3. Perceived
Causes of Beltway Crashes.

Perceived Crash Causes

Percent
General
Drivers
(N=32)

Percent
Aggressive
Drivers
(N=20)

Percent
1997
Total
(N=52)

Percent
1994
Total
(N=64)

Unsafe Driving (Cumulative):

166

205

181

95

Speed

38

65

48

23

Aggressive Drivers

53

15

38

2

Inattention

28

30

29

19

Car Phones

0

0

0

--

Moms Watching Kids

--

0

0

--

Unsafe Lane Changing

0

35

13

17

Weaving

--

0

0

--

Tailgating

13

15

13

2

Slow Drivers

0

20

8

3

Left Lane Etiquette

9

0

6

11

DUI/DUID

3

10

6

0

Tired Drivers

6

--

4

0

Rubberneckers

6

0

4

0

Indecisive Drivers

6

--

4

3

Unnecessary Braking

--

10

4

2

Not Signaling

3

--

2

0

Cutting Off Trucks

0

--

0

--

Not Yielding

--

5

2

2

Racing/Showing Off

--

0

0

0

Backing Up on Beltway

--

0

0

--

Not Moving Away From Safety Vehicle

--

0

0

--

Driving on Shoulder

--

0

0

--

Last Minute Lane Changes

--

0

0

--

Stopping in Merge Lane

--

0

0

--

Headlight Flashing

0

--

0

--

Timid Drivers

--

0

0

0

Menacing Drivers (Guns, etc.)

--

0

0

--

Revenge

--

0

0

--

Carelessness (General)

--

--

--

8

Driver Error (General)

--

--

--

5

Driving Conditions (Cumulative):

75

50

65

53

Weather

34

40

37

9

Congestion (Rush Hour)

31

10

23

44

Poor Visibility (Night)

9

--

6

--

Bright Sun

0

--

0

--

Roadway Design and Maintenance:

38

25

33

97

Merge Lanes (Shared Acceleration/Deceleration)

25

20

23

27

Construction

6

0

4

11

Ambiguous/Incorrect Construction Signs

--

--

--

3

Unclear Lane Markings

0

0

0

8

Confusing Signs

0

5

2

17

Inadequate Exit Signs

3

--

2

--

Road Design

3

--

2

--

On/Off Ramps on Opposite Sides

0

--

0

--

Springfield Interchange

0

--

0

--

Short Ramps/Clogged Ramps

0

0

0

--

Potholes

0

--

0

2

Exits With No Merge Lane

--

0

0

0

Lane Drops

--

--

--

9

Inconsistent Ramp Design

--

--

--

5

Poor Snow Removal

--

--

--

5

Debris on Road

--

--

--

3

Short Acceleration Lanes

--

--

--

3

Uneven Road (When Paving)

--

--

--

2

Other Design Features

--

--

--

3

Trucks (Cumulative):

3

5

4

20

Trucks

3

--

2

14

Debris from Trucks/Uncovered Trucks

0

5

2

--

Heavy Equipment/Large Vehicles

--

5

2

--

Trucks In Fast Lane

--

0

0

--

HAZMATS

--

0

0

--

Truck Maintenance

--

--

--

6

Law Enforcement (Cumulative):

0

0

0

2

Law Enforcement Activity

0

0

0

0

Lack of Law Enforcement

0

0

0

2

Speed Limit Too Low

--

--

0

0

Other:

6

0

4

2

Poorly Trained (Inexperienced) Drivers

6

--

4

2

Out of Town Drivers

0

0

0

--

Taxi Drivers

0

--

0

--

Foreign Drivers

--

0

0

--

Diplomats

--

0

0

--

Unsafe Vehicles

--

0

0

--

Not Wearing Seat Belts

0

--

0

--

Blind Spots

0

--

0

--

Media Activity

--

0

0

--

The following list
of crash causes was compiled in the three trucking company groups. Interviewing
conditions made it difficult to get each participant to designate his
top three causes as in the driver groups, but it was accomplished in the
group of dump truck drivers. The table shows the number of participants
ranking each problem among his top three. In all other cases, the mention
of each crash cause is shown as a check mark ().

Table 4. Perceived
Causes of Beltway Crashes - Commercial Drivers.

Perceived Crash Causes

Skippy's
# Serious

Roadway
Express

North
American

Dangerous Driving Behavior:

Lane Switching

3

Speed

3

Aggressive Driving

2

Slow Drivers in Left Lane

2

Slow Drivers

1

Irresponsible Drivers

1

Tailgating

1

Bumper Tag

1

Fatigue (Truck Drivers and Others)

1

No Turn Signals

Driver Rage

Shouldering

Lack of Anticipation

Inattention

Failure to Yield

Blocking Trucks from Changing Lanes

Driving in Truck Blind Spot

Rubbernecking

Driving Conditions:

Congestion

Roadway Design and Maintenance:

Woodrow Wilson Bridge

1

Construction (Especially Daytime)

HOV Lane Entrances and Exits (I-66)

Springfield Interchange

Curves (Between I-270 and College Park)

Washboard Pavement

Lane Drops

Left Exits

Narrow Lanes in Work Areas

Law Enforcement:

Insufficient Law Enforcement Presence

2

Law Enforcement Stops

Blue Lights

Cops Writing Warnings, Not Tickets

Poor Law Enforcement Priorities

Other:

Non-English Speaking Drivers

Poorly Trained Drivers

Disabled Vehicles in Travel Lanes

Large Recreational Vehicles

Like other Beltway
users, the truck drivers' list of crash causes was heavily weighted toward
dangerous driving behavior. They were somewhat less inclined than other
drivers to blame Beltway crashes on driving conditions but congestion
was mentioned in every truck driver group. Roadway Design factors were
mentioned fairly often in the trucker groups as they were among other
drivers. Law enforcement (or the lack of it ) was mentioned more among
the truck drivers than among other drivers.